The original story, as it appeared in the September 1988 issue of Modern Photography. Note the negative, reproduced on the bottom left.
Bill Eppridge's photo of Robert F. Kennedy lying in a pool of blood on the kitchen floor—iconic, tragic, emotional—was in fact, one of the most difficult images to print. It had been printed once, and all future prints were made from a copy negative of that print.
For the article, the original negative was pulled from the file where had stayed, untouched, for nearly 20 years, in a 5x7-inch glassine envelope. Luis Barrios, the darkroom technician who originally printed it in 1968, would re-trace his steps that nearly 20 years later, to the day.
I held the historic negative in my shaking, white gloved hands. The first thing I noticed was that the negative was scratched and bent, and had almost no shadow detail. In fact, there was very little there at all. I wondered how any image could be coaxed out of it.
But I knew that the Time-Life darkroom techs were the unsung heroes of photojournalism in their day, and that they had many tricks up their sleeves. Luis got to work. Here's what I wrote in Modern:
We've all been haunted by this one, but not as much as Luis Barrios, the technician called upon to print it. The problem is that the negative is extremely thin, but with a couple of spots of intense highlights. The busboy's face is barely visible in the negative, but his helpless reaction, as well as Robert Kennedy's highly-lit profile, made this photo part of our collective memory.
The first print, on Kodak Polyfiber with a #1 1/2 filter, was exposed for four seconds at f/11. It showed us that the negative was a mess. Newton rings indicated there was grease on the negative or the glass carrier that was used to prevent the negative from buckling; there was a bend in the negative that showed up as a silver moon; there were scratches everywhere and the overall image looked muddy.
The negative and glass carrier were treated with negative cleaner, but the Newton rings didn't disappear, so Luis switched to a non-glass negative carrier. He rubbed some forehead grease onto the negative to eliminate most of the scratches (the grease was removed later with Xylene cleaner.) To get rid of the muddiness and give him control over burning in the bend, he chose a #5 filter.
Luis opened the lens half a stop and increased his exposure to five seconds to compensate for the density of the filter. He burned around the sides for a few seconds. In developer, he used hot water to bring up details in the highlights on Kennedy's face, and around the lower left side to darken it. As a result, the picture seemed to be framed in a rich black that eliminated most of the scratches.
However, the waiter's face was barely visible under the higher contrast, and his shirt looked dirty rather than underexposed. Kennedy's face was extremely contrasty. The print also still looked a bit muddy overall. Luis switched to Kodabromide, grade five.
A basic exposure of five seconds at f/11 was established. Luis dodged the waiter's face for a bit over a second, then the shadowy part of Kennedy's face for a little less than a second, then the waiter's shirt for a moment. Then, working slowly and deliberately, he allowed light onto the highlight on Kennedy's face, small portions at a time.
Now highlight and shadow details emerged. In the Dektol, hot water was run onto the dark areas for emphasis. In the fixer, Luis dipped a Q-tip in potassium ferricyanide bleach and gently stroked the print with it. As he carefully added bleach to the shadow part of Kenndy's face and the waiter's face and shirt, more details emerged. We inspected the print: this was it.